get_vital_rates_data = function(){
    fn = '../../Data/vital_rates.dat'
    DF = read.table(fn, header=FALSE, skip=0, na.strings='.', col.names=c('Year', 'All_cause', 'Heart_disease', 'Cancer', 'Stroke', 'Respiratory_disease', 'Unintentional_injury'), fill=TRUE, stringsAsFactors=FALSE)
    DF$Year = sapply(DF$Year, function(x){as.numeric(gsub('\\*', '', x))})
    DF$All_cause = sapply(DF$All_cause, function(x){as.numeric(gsub(',', '', x))})
    DF
}